Process for preparing silylorganomercaptans

Abstract

A process for preparing an organomercaptan is provided which comprises reacting a sulfide of the general formula (I)in which each R1 is the same or different alkyl group of up to about 6 carbon atoms, aryl group of up to about 10 carbon atoms or alkoxy group of up to about 6 carbon atoms, or at least two of R1 and the silicon atom to which they are bonded form a ring system having up to about 12 ring members with no ethylenic unsaturation and optionally containing one or more heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, each R2 is the same or different divalent hydrocarbon group containing no ethylenic unsaturation and having up to about 20 carbon atoms and m is 0 to about 8, with hydrogen under hydrogenolysis conditions in the presence of a catalytically effective amount of Group VIII metal catalyst and in the presence of a catalyst poisoning inhibiting amount of a catalyst poisoning inhibitory agent selected from the group consisting of water, except where the mercaptan product contains at least one hydrolyzable silane group, alkanol of from 1 to about 6 carbon atoms, hydrogen sulfide and mixtures thereof to provide organomercaptan product of the general formula (II)in which R1 and R2 each has one of the aforestated meanings.

What is claimed is:  
     
       1. Process for preparing an organomercaptan which comprises reacting a sulfide of the general formula (I)                    
       in which each R 1  is the same or different alkyl group of up to about 6 carbon atoms, aryl group of up to about 10 carbon atoms or alkoxy group of up to about 6 carbon atoms, or at least two of R 1  and the silicon atom to which they are bonded form a ring system having up to about 12 ring members with no ethylenic unsaturation and optionally containing one or more heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, each R 2  is the same or different divalent hydrocarbon group containing no ethylenic unsaturation and having up to about 20 carbon atoms and m is 0 to about 8, with hydrogen under hydrogenolysis conditions in the presence of a catalytically effective amount of Group VIII metal catalyst and in the presence of a catalyst poisoning inhibiting amount of a catalyst poisoning inhibitory agent selected from the group consisting of water, except where the mercaptan product contains at least one hydrolyzable silane group, alkanol of from 1 to about 6 carbon atoms, hydrogen sulfide and mixtures thereof to provide organomercaptan product of the general formula (II) 
       
         
           (R 1 ) 3 —Si—R 2 —SH  (II)  
         
       
       in which R 1  and R 2  each has one of the aforestated meanings. 
     
     
       2. The process of  claim 1  wherein at least one R 1  is an alkyl group selected from the group consisting of methyl, ethyl, propyl and butyl. 
     
     
       3. The process of  claim 1  wherein at least one R 1  is a phenyl group. 
     
     
       4. The process of  claim 1  wherein at least one R 1  is an alkoxy group selected from the group consisting of methoxy, ethoxy, propoxy or butoxy. 
     
     
       5. The process of  claim 1  wherein each R 2  is the same or different divalent alkylene radical of up to about 12 carbon atoms. 
     
     
       6. The process of  claim 5  wherein each R 2  is the same or different divalent alkylene radical selected from the group consisting of methylene, ethylene, 1,2-propylene, 2-methyl-1,3-propylene, 3-methyl-1,3-propylene, 3,3-dimethyl-1,3-propylene, ethylidene or isopropylene, cyclohexylene, cycloheptylene, phenylene, tolylene, xylylene and naphthylene. 
     
     
       7. The process of  claim 1  wherein m is 0 to 4. 
     
     
       8. The process of  claim 2  wherein m is 0 to 4. 
     
     
       9. The process of  claim 3  wherein m is 0 to 4. 
     
     
       10. The process of  claim 4  wherein m is 0 to 4. 
     
     
       11. The process of  claim 5  wherein m is 0 to 4. 
     
     
       12. The process of  claim 6  wherein m is 0 to 4. 
     
     
       13. The process of  claim 1  wherein sulfide (I) is a disilylalkyldisulfide selected from the group consisting of bis[3-(triethoxysilyl)propyl]disulfide, bis[3-(trimethoxysilyl)propyl]disulfide, 4,13-diethoxy-4,13-dimethyl-3,14-dioxa-8,9-dithia-4,13-disilahexadecane, 4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane, 8,11-dimethyl-5,5,14,14- tetrapropoxy-4,15-dioxa-9,10-dithia-5,14-disilaoctadecane, 3,3,12,12-tetramethoxy-6,9-dimethyl-2,13-dioxa-7,8-dithia-3,12-disilatetradecane, 3,3,12,12-tetramethoxy-4,11-dimethyl-2,13-dioxa-7,8-dithia-3,12-disilatetradecane, 6,13-dimethyl-5,5,14,14-tetrapropoxy-4,15-dioxa-9,10-dithia-5,14-disilaoctadecane, bis[3-(tributoxysilyl)propyl]disulfide and 5,14-diethyl-3,16-dimethyl-5,14-bis(1-methylpropoxy)-4,15-dioxa-9,10-dithia-5,14-disilaoctadecane. 
     
     
       14. The process of  claim 1  wherein sulfide (I) is a disilylalkyltrisulfide selected from the group consisting of bis[3-(triethoxysilyl)propyl]trisulfide, bis[3-(trimethoxysilyl)propyl]trisulfide, bis[3-(triisopropoxysilyl)propyl] trisulfide, 3,13-dibutyl-3,13-dimethoxy-2,14-dioxa-7,8,9-trithia-3,13-disilapentadecane, 3-(tributoxysilyl)propyl 3-(trimethoxysilyl)propyl trisulfide, (trithiodi-3,1-propanediyl)bis[tris(cyclopentyloxy)-silane and 5,21-diethyl-8,8,18,18-tetrakis[(2-ethylhexyl)oxy]-7, 19-dioxa-12,13,14-trithia-8,18-disilapentacosane. 
     
     
       15. The process of  claim 1  wherein sulfide (I) is a disilylalkyltetrasulfide selected from the group consisting of bis[3-(trimethoxysilyl)propyl]tetrasulfide, (tetrathiodi-3,1-propanediyl)bis[tris(isooctyloxy)-silane, bis[3-triethoxysilyl)propyl] tetrasulfide, 4,4-diethoxy-15,15-bis(ethoxymethoxy)-3,16,18-trioxa-8,9,10,11-tetrathia4,15-disilaeicosane, 6,6,17,17-tetrakis(ethoxymethoxy)-3,5,18,20-tetraoxa-10,11,12,13-tetrathia-6,17-disiladocosane, 1,1′-(tetrathiodi-3,1-propanediyl)bis-2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecane, bis[3-(diethoxymethylsilyl)propyl]tetrasulfide, 2,17-dimethyl-4,4,15,15-tetrakis(1-methylethoxy)-3,16-dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane, 4,4,15,15-tetraethoxy-7,12-dimethyl-3,16- dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane, 5,16,16,-triethoxy-5-methoxy4,17-dioxa-9,10,11,12-tetrathia-5,16-disilaheneicosane, 6,6,17,17-tetrabutoxy-5,18-dioxa-10,11,12,13-tetrathia-6,17-disiladocosane, 3,3,14,14-tetramethoxy-5,12-dimethyl-2,15-dioxa-7,8,9,10-tetrathia-3,14-disilahexadecane, 3,14-bis(1,1-dimethylethyl)-3,14-dimethoxy-2,15-dioxa-7,8,9,10-tetrathia-3,14-disilahexadecane, disilatriacontane, 10,10,21,21-tetrakis(octyloxy)-9,22-dioxa-14,15,16,17-tetrathia-10,21-disilatriacontane, 10,21-diethoxy-10,21-bis(octyloxy)-9,22-dioxa-14,15,16,17-tetrathia-10,21-disilatriacontane, 10,10,21-triethoxy-21-(octyloxy)-9,22-dioxa-14,15,16,17-tetrathia-10,21-disilatriacontane, tetrathiodi-3,1-propanediyl)bis[tris(cyclohexyloxy)-silane, 3,14-dimethoxy-3,14-diphenyl-2,15-dioxa-7,8,9,10-tetrathia-3,14-disilahexadecane, 6,17-diethoxy-6,17-diphenyl-5,18-dioxa-10,11,12,13-tetrathia-6,17-disiladocosane, 14-ethoxy-3,3-dimethoxy-14-phenyl-2,15-dioxa-7,8,9,10-tetrathia-3,14-disilanonadecane and 3,3,14,14-tetramethoxy-6,11-diphenyl-2,15-dioxa-7,8,9,10-tetrathia-3,14-disilahexadecane. 
     
     
       16. The process of  claim 1  wherein the hydrogenolysis conditions include a hydrogen pressure of from about 300 psig to about 600 psig, a temperature of from about 160° C. to about 190° C. and a reaction time of from about 2 hours to about 5 hours. 
     
     
       17. The process of  claim 1  wherein the Group VIII metal catalyst is nonsupported or supported and contains at least one metal selected from the group consisting of nickel, cobalt, rhodium and ruthenium. 
     
     
       18. The process of  claim 1  wherein the catalyst is present at from about 1 to about 10 weight percent by weight of sulfide (I). 
     
     
       19. The process of  claim 1  wherein the alkanol is selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol and isobutanol. 
     
     
       20. The process of  claim 1  wherein the catalyst poisoning inhibitory agent is present in an amount of from about 5 to about 50 weight percent by weight of sulfide (I).